title: High-molecular-weight penicillin-binding proteins from membranes of bacilli.
abstract: Mixtures of high-molecular-weight, cephalosporin-sensitive penicillin-binding proteins (PBPs) can be purified from Bacillus subtilis membranes by cephalosporin affinity chromatography (G. Kleppe and J. L. Strominger, J. Biol. Chem. 254:4856-4862, 1979). By appropriate modification of this technique, B. subtilis PBP 1 was purified to homogeneity, and a mixture of Bacillus stearothermophilus PBPs 1, 2, and 4 was isolated. [14C]penicillin-PBP complexes of high-molecular-weight PBPs purified from membranes of these two bacilli, after denaturation, were found to have chemical reactivities typical of the penicilloyl-serine derivative formed by D-alanine carboxypeptidase from B. stearothermophilus. Although enzymatic activity catalyzed by these and several other high-molecular-weight PBPs from gram-positive organisms has not been detected with cell wall-related substrates, a slow, enzymatic acylation of B. subtilis PBPs 1, 2ab, and 4 by [14C]-diacetyl-L-lysyl-D-alanyl-D-lactate was demonstrated. Further study is necessary to clarify the physiological relevance of the slow acylation by this analog of a natural cell wall biosynthetic intermediate.
mesh_terms: D000215:Acylation; D001412:Bacillus subtilis / Q000032:analysis*; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D002511:Cephalosporins / Q000494:pharmacology; D055598:Chemical Phenomena; D002621:Chemistry; D006602:Hexosyltransferases; D008970:Molecular Weight; D002267:Muramoylpentapeptide Carboxypeptidase; D010400:Penicillin G / Q000378:metabolism; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D002511:Cephalosporins; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D010400:Penicillin G